Twin tube car drive

ABSTRACT

A propulsion system for the cars of a transportation system in which cars are guided along predetermined pathways having favorable stability and noise-suppression characteristics. The system comprises (1) a pair of cylindrical tubes mounted on each of the cars, journalled for rotation relative to the car on which they are mounted, and extended longitudinally of the car in parallel, spaced relationship to each other, (2) two sets of wheels spaced along the predetermined pathways and journalled for rotation, one set being positioned to engage the cylindrical surface of one of the tubes on each of the cars and the other set being positioned to engage the cylindrical surfaces of the other tube on each of the cars, and (3) means for driving either the tubes or the wheels. In the preferred embodiment, the angles between the axes of the tubes and the axes of the wheels is variable so that the speed of the cars can be varied by varying that angle without varying the speed of the member to which power is supplied.

United States Patent [191 Broome Dec. 17, 1974 [21] Appl. No.: 396,965

[52] US. Cl. 104/166 [51] Int. Cl B61b 13/00 [58] Field of Search 104/166, 167, 168, 147 R;

180/7 R, 7 A, 6.2; 74/194; 105/26 D; 191/45 Primary ExaminerLloyd L. King Assistant ExaminerRandolph A. Reese Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak 57 ABSTRACT A propulsion system for the cars of a transportation system in which cars are guided along predetermined pathways having favorable stability and noisesuppression characteristics. The system comprises l a pair of cylindrical tubes mounted on each of the 7 cars, journalled for rotation relative to the car on which they are mounted, and extended longitudinally of the car in parallel, spaced relationship to each other, (2) two sets of wheels spaced along the predetermined pathways and journalled for rotation, one set being positioned to engage the cylindrical surface of one of the tubes on each of the cars and the other set being positioned to engage the cylindrical surfaces of the other tube on each of the cars, and (3) means for driving either the tubes or the wheels. 1n the preferred embodiment, the angles between the axes, of the tubes and the axes of the wheels is variable so that the speed of the cars can be varied by varying that angle without varying the speed of the member to which power is supplied.

6 Claims, 2 Drawing Figures PATENIHJ DEC 1 U974 TWIN TUBE CAR DRIVE FIELD OF THE INVENTION This invention relates generally to the transmission of power to the cars of a friction-powered unit transportation system and, more specifically, to the transmission of power to the cars in a transportation system such as is disclosed in commonly assigned US. Pat. Nos. 3,621,790, 3,626,859, and 3,650,216.

BACKGROUND OF THE INVENTION In friction-powered unit transportation systems such as are disclosed in the above-listed patents, the interaction of the ground-mounted wheels with the single carmounted tubes causes the cars to tend to shift laterally with respect to the predetermined pathway. Thistendency has to be compensated for by some lateral guide means such as are disclosed in those patents. These lateral guide means can adversely affect thestability of the cars, and they almost inherently add very appreciably to the noise generated by the system, which can be very undesirable in some applications. Additionally, to the extent that the lateral guide means support the weight of the cars, they subtract from the force between the tubes and the wheels, thereby reducing the available drive power and thus the accelerational and climbing capabilities of the system.

OBJECT OF THE INVENTION In view of the above-mentioned drawbacks to the prior art, the principal object of the present invention is to provide a propulsion system for friction-powered unit transportation systems such as is disclosed in the above patents which imparts little or no tendency to shift laterally from the predetermined path to the cars of the unit transportation system and which can therefore use no lateral guides or lateral guides which are greatly reduced in size and strength in comparison to the lateral guides used in the system disclosed in the above-mentioned patents. Secondary objects of the present invention include providing a propulsion system for such a friction-powered unit transportation system which is appreciably quieter than the previously used propulsion systems and which utilizes an appreciably higher percentage of the available weight of the cars in the system, thereby enhancing the accelerational and incline-climbing properties of the system.

SUMMARY OF THE INVENTION The above objects are accomplished by a system which comprises (1) a pair of cylindrical tubes mounted on each of the cars, journalled for rotation relative to the car on which they are mounted, and extended longitudinally of the car in parallel, spaced relationship to each other, (2) two sets of wheels spaced along the predetermined pathways and journalled for rotation, one set being positioned to engage the cylindrical surface of one of the tubes on each of the cars and the other set being positioned to engage the cylindrical surfaces of the other tube on each of the cars, and (3) means for driving either the tubes or the wheels. 1n the preferred embodiment, the angles between the axes of the tubes and the axes of the wheels is variable so that the speed of the cars can be varied by varying that angle without varying the speed of the member to which power is supplied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end view of a preferred embodiment of the present invention with details of the structure of the car omitted.

FIG. 2 is a plan view of the embodiment of the present invention shown in FIG. 1 with the superstructure of the car shown only in phantom outline.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the figures, a car 10 is shown moving over a predetermined pathway 12. Mounted transverse to the direction of the predetermined pathway 12 are ties 14, which may be conventional railway ties, for example. A pair of reaction wheels 16, 18 are mounted on each tie 14 or, in general, at intervals sufficiently close so that the smooth-surfaced drive cylinders 20, 22 mounted on the bottom of the car 10 are always in contact with at least two pairs of the reaction wheels 16, 18. The reaction wheels 16, 18 are mounted in journalling means 24, 26 which permit the reaction wheels 16, 18 to rotate freely. It will be observed that, when the rotational axes of the reaction wheels 16, 18 are set at an angle to the longitudinal axes of the drive cylinders 20, 22, as shown in the drawings, the reaction wheels 16, 18 will trace a helical path on each drive tube surface the pitch of which varies according to the angle between their respective axes. Preferably, the journalling means 24, 26 are pivotably mounted in the pathway 12 so that the angle the axis of the wheels journalled therein make with the longitudinal axis of the pathway at the points where the wheels are positioned can be varied. Suitable means for so mounting the journalling means are disclosed in my previously issued, commonly assigned US. Pat. No. 3,621,790, the relevant disclosure from which is hereby expressly incorporated by reference herein. The purpose of so mounting the journaling means is so that the power transmitted between the reaction wheels 16, 18 and the drive cylinders 20, 22 can be varied by varying the abovementioned angle without varying the rotational speed of the drive cylinder. Obviously, it is usually preferable to connect adjacent pairs of reaction wheels 16, 18 so that the absolute values of the angles the axes of the wheel journaled by each means in such a pair make with the longitudinal axis of the pathway are always equal, but the sense of the angles are opposite. This relationship is illustrated in the drawing.

The drive cylinders 20, 22 are resiliently mounted on the car 10 by means such as the V-shaped axes 28 mounted at either end of the car in the preferred embodiment. Joumalling means are provided where the shafts 29 of the cylinders 20, 22 meet the axes 28 to allow the shafts to rotate freely. Since the cars in systems such as these are supported either largely or entirely by their cylinders, the resilient mounting means serve the same function as shock absorbers in more conventional transportation systems.

A motor 30 is mounted on the bottom of the car 10 between the drive cylinders 20, 22, and it powers the drive cylinders 20, 22 by means of sheaves 32 mounted on its drive shaft 31, sheaves 34 mounted on the shafts 29 of the drive cylinders 20, 22, and connecting belts 36.

The motor 30 may be powered by any appropriate means, but it has been found particularly convenient to power it electrically. This may be done by means of an electrified rail 38 and an electrical ground rail 40, one of which is mounted on either side of the pathway 12. Means for picking up the power from the electrified rail 38 and for completing the circuit are provided in the form of V-mounted rollers 42 and brushes 44. The rollers 42 cooperate physically with each other and with the rails with which they are in contact to prevent lateral shifting of the car 10 on the wheels l6, l8, and they can also serve as electrical connectors instead of or in addition to the brushes 44. In some applications, it may be possible to dispense with the rollers 42 altogether, since, in some applications, cars made according to this invention may not require the lateral support which such rollers supply. The brushes 44 and/or the rollers 42 are electrically connected to the motor 30 by conventional means (not shown).

CAVEAT While the present invention has been illustrated by a detailed description of a preferred embodiment thereof, it will be obvious to those skilled in the art that various changes in form and detail can be made therein without departing from the true scope of the invention. For instance, the wheels 16, 18 could be driven and the cylinders 20, 22 could be unpowered as is shown, for instance, in a similar system in commonly assigned US. patent application 309,027, filed Nov. 24, 1972-, the cylinders dont have to extend over such a large percentage of the length of the car, the motor could be mounted elsewhere, etc. Accordingly, the invention must be measured by the claims appended hereto and not by the foregoing preferred embodiment.

What is claimed is:

l. A propulsion system for an individual car of a transportation system in which the cars are guided along predetermined pathways, said propulsion system comprising:

a. a pair of cylindrical tubes extending longitudinally of the car in parallel, spaced relationship to each other;

b. means mounted on said car for journalling said tubes for rotation about their axes;

c. a first plurality of wheels mounted in the predetermined pathways in position to engage the cylindrical surfaces of one of said pair of tubes, said first plurality of wheels being pivotably mounted in the predetermined pathways so that the angle the axis of each wheel makes with the longitudinal axis of the pathway at the point where that wheel is mounted can be varied;

d. a second plurality of wheels mounted in the prededetermined pathways in position to engage the cylindrical surfaces of the other of said pair of tubes, each one of said second plurality of wheels being mounted opposite a corresponding one of said first plurality of wheels with reference to the longitudinal axis of the pathway at the point where that wheel is mounted, said second plurality of wheels likewise being pivotably mounted so that the angle the axis of each wheel makes with the longitudinal axis of the pathway at the point where that wheel is mounted can be varied; e. means journalling said first and second plurality of wheels for rotation about their axes;

f. means operatively connecting corresponding wheels of said first and second plurality of wheels so that the absolute value of the angle the axis of each makes with the longitudinal axis of the pathway at the point where they are mounted is always equal, but the sense of the angle is opposite; and

g. power means operatively arranged to drive the system comprising said tubes and said reaction wheels.

2. A propulsion system as claimed in claim 1 wherein said power means are mounted on the car and are operatively connected to said tubes.

3. A propulsion system as claimed in claim 1 wherein said power means are electrically powered, an electrified rail is mounted in the predetermined pathway, means for picking up the power from said electrified rail are mounted on the car in position to engage said electrified rail, and said means for picking up the power from said electrified rail and said electrified rail cooperate physically to prevent lateral shifting of the car on said wheels.

4. A propulsion system as claimed in claim 3 wherein an electrical ground rail is also mounted in the predetermined pathway in parallel relationship to said electrified rail;

means for completing the circuit from said electrified rail to said electrical ground rail are mounted on the car in position to engage said electrical ground rail; and

said means for picking up the power from said electrified rail and said means for completing the circuit cooperate physically with each other and with the rails with which they are respectively associated to prevent lateral shifting of the car on said wheels.

5. A propulsion system as claimed in claim 4 wherein said means for picking up the power from said electrified rail and said means for completing the circuit each comprises a conductive roller mounted for rotation along a vertical surface of the rail associated therewith.

6. A propulsion system as claimed in claim 1 wherein said tubes are resiliently mounted on the car. 

1. A propulsion system for an individual car of a transportation system in which the cars are guided along predetermined pathways, said propulsion system comprising: a. a pair of cylindrical tubes extending longitudinally of the car in parallel, spaced relationship to each other; b. means mounted on said car for journalling said tubes for rotation about their axes; c. a first plurality of wheels mounted in the predetermined pathways in position to engage the cylindrical surfaces of one of said pair of tubes, said first plurality of wheels being pivotably mounted in the predetermined pathways so that the angle the axis of each wheel makes with the longitudinal axis of the pathway at the point where that wheel is mounted can be varied; d. a second plurality of wheels mounted in the prededetermined pathways in position to engage the cylindrical surfaces of the other of said pair of tubes, each one of said second plurality of wheels being mounted opposite a corresponding one of said first plurality of wheels with reference to the longitudinal axis of the pathway at the point where that wheel is mounted, said second plurality of wheels likewise being pivotably mounted so that the angle the axis of each wheel makes with the longitudinal axis of the pathway at the point where that wheel is mounted can be varied; e. means journalling said first and second plurality of wheels for rotation about their axes; f. means operatively connecting corresponding wheels of said first and second plurality of wheels so that the absolute value of the angle the axis of each makes with the longitudinal axis of the pathway at the point where they are mounted is always equal, but the sense of the angle is opposite; and g. power means operatively arranged to drive the system comprising said tubes and said reaction wheels.
 2. A propulsion system as claimed in claim 1 wherein said power means are mounted on the car and are operatively connected to said tubes.
 3. A propulsion system as claimed in claim 1 wherein said power means are electrically powered, an electrified rail is mounted in the predetermined pathway, means for picking up the power from said electrified rail are mounted on the car in position to engage said electrified rail, and said means for picking up the power from Said electrified rail and said electrified rail cooperate physically to prevent lateral shifting of the car on said wheels.
 4. A propulsion system as claimed in claim 3 wherein an electrical ground rail is also mounted in the predetermined pathway in parallel relationship to said electrified rail; means for completing the circuit from said electrified rail to said electrical ground rail are mounted on the car in position to engage said electrical ground rail; and said means for picking up the power from said electrified rail and said means for completing the circuit cooperate physically with each other and with the rails with which they are respectively associated to prevent lateral shifting of the car on said wheels.
 5. A propulsion system as claimed in claim 4 wherein said means for picking up the power from said electrified rail and said means for completing the circuit each comprises a conductive roller mounted for rotation along a vertical surface of the rail associated therewith.
 6. A propulsion system as claimed in claim 1 wherein said tubes are resiliently mounted on the car. 